1. Field of the invention
The present invention relates to a bio-sensor using an ion-sensitive field effect transistor (ISFET) which has a platinum(Pt) electrode, which allows extremely to sensing characteristic.
2. Description of the Related Art
Bio-sensors for sensing biological substances are widely employed in the fields of medical diagnosis, fundamental science, food engineering and the like. Typically, conventional bio-sensors include a spectrophotometer or glass electrode, and are disadvantageous in that they are relatively large in size, very expensive and difficult to handle.
Accordingly, many attempts have been made to obtain a bio-sensor to which overcomes the aforementioned disadvantages in the fields of medical diagnosis and food engineering. To satisfactory the aforementioned demand, an ion sensitive FET (ISFET), known as a semiconductor ion sensor, has been proposed.
Since the bio-sensor employing an ISFET is fabricated by the integrated circuit process technology, it has many advantages, such as small size, mass producibility and ease of standardization. As a result, it has been considered that the potential for developing a bio-sensor satisfying the aforementioned demand is very great.
Such a bio-sensor employing an ISFET developed heretofore, however, has small sensitivity and long response time. As a result, it is difficult to employ the bio sensor for practical use.